[…] There are other devices that do similar things, but the CurrentCost has a serial port through which it outputs its readings every 6 seconds or so, which means you can use the data for whatever you like. It’s even in XML. […]

Probably just me being slow, but I found the two-hour totals a bit confusing at first.

I think I’ve got it sussed now – in case it is helpful for anyone else looking at this for the first time, they seem to be two-hour buckets giving the total since the last “even” hour?

For example, consider the hourly history data you would get at 7.41pm

h2 contains total for 18:00 to 20:00
h4 contains total for 16:00 to 18:00
h6 contains total for 14:00 to 16:00
h8 contains total for 12:00 to 14:00
h10 contains total for 10:00 to 12:00
h12 contains total for 8:00 to 10:00
h14 contains total for 6:00 to 8:00
h16 contains total for 4:00 to 6:00
h18 contains total for 2:00 to 4:00
h20 contains total for 0:00 to 2:00
h22 contains total for 22:00 (yesterday) to 0:00
h24 contains total for 20:00 (yesterday) to 22:00 (yesterday)
h26 contains total for 18:00 (yesterday) to 20:00 (yesterday)

Looking at it like that, it makes sense to me now why there are 13 updates – it means you can get twenty-four hours worth of updates.

I’ve been following your experiments with interest and have bought a Current Cost. Unfortunately I seem to have a 2400 baud device which only spits out the current data, not the history (on an RJ45 though). Any ideas how to get one with history? Can you configure it? Cheers.

Hi Tristan
there are two models of currentcost meter in circulation – the slightly older one runs at 2400 baud and doesn’t store history.
The newer one runs at 9600 baud and does have history.
The power companies have the older ones in stock at the moment… :(

[…] clunky, and I’m convinced that I’m not reading the hourly data quite right (the data is received from the CurrentCost meter in a confusingly-labelled way giving relative times, and I think I’m translating it into actual times […]

Hi,
I am using a current-cost meter that sends the current energy every 6 seconds in watts and I am storing these values in the database i.e. currentEnergy = currentEnergy + liveEnergy and counter = counter + 1 so at the end of the day i m having the total sampled value and total no of sample with sampling rate as 1 sample in every 6 seconds and they are 10097246 Watts & 10976 samples. if i divide the total sampled energy with total no of samples i.e. 10097246/10976 = 919.94 Watts per sample. How do i calculate the kW-hr for that day??

If anyone is interested, I made a small perl script to read CurrentCost XML data and update http://www.pachube.com/ feed with current power readings (in watts). It can work with multiple sensors and multiple channels too.